The rental of television sets generates considerable revenue in public facilities such as hospitals and hotels and various systems have been developed to ensure that fees are collected when the television sets are used. Early systems involving signal scrambling and/or the use of credit cards, tokens or cash were not wholely satisfactory and were replaced with computer based systems wherein the charge or billing information was determined by central computer that polled the channel selection of each set and accumulated a charge for its usage. A problem with this type of system was that if the central computer should fail, all of the current billing charge information was lost.
A more recent system provides on each television set a microprocessor for monitoring the set usage and developing billing information, and a non-volatile memory for storing the information developed. A central computer may access the memory and after it retrieves the billing information the central computer may clear the memory. While this system avoids the loss of billing information, it lacks several features desirable when it is used in a hospital. For example, if a patient should be moved from one room to another, the prior art system requires the generation of two separate charges for television usage, that is, one charge for usage of the television set in each room. Also, the prior art system does not provide for complete control over the television sets from the central computer. This is desirable when the hospital desires to have the patient see an instructional video program concerning an operation he is about to undergo, or a diet or course of rehabilitation he should follow after leaving the hospital.
Furthermore, the prior art system is limited in that billing is based only on the time of viewing of premium channels; no provision is made for changing tiers, that is, channels which the patient may view, and no provision is made for changing the channels in a group of channels for which a premium will be charged.